How to Be a Helpful Mock Interviewer
If you are reading this and are a student, there's a good chance you are interested in recruiting for consulting roles. There is also a great chance you are not the only one you know in that boat. In a recruiting season, you could trade cases with dozens of other casers (they're your competition, but maybe also your friends). Since you're all in this together, I often get asked how to give better mock interviews as someone without consulting experience. While everyone needs specific, personalized guidance to make the biggest improvements possible, I think focusing on three areas can make a material difference for most.
First, know your cases cold. Reuse cases with different people. Give them to yourself. Know the math inside and out. Learn the areas where you can get more nuanced for stronger casers and more high level for new casers. Knowing all of this means your focus will be on the caser, not the case, so you'll have more mental energy to spend on identifying areas of growth. Additionally, you'll be better able to guide the interviewee back on track if needed, and you'll be able to conduct the case competently and confidently, like a real interviewer.
Second, be specific in your feedback. Saying "You did badly" is not useful to anyone. When you point out an area of improvement, specify what they did, explain the issue with that, and suggest how to improve. To the point above, learn what good looks like from the stronger casers that you interviewed and use that knowledge to help newer casers.
Lastly, limit the feedback to a few major points. If you spend your debrief listing 20 small mistakes, the caser won't know how to prioritize and probably won't retain most of the feedback. Stick to three topics and go deeper. Focus on the "small hinge that swings a big door" (consultants love analogies).
What goes around comes around. Be a better interviewer, train others to be better, and you'll get better feedback and improve faster.
Or, you know, work with an experienced coach.
How many cases should I do?
"It really doesn’t matter how long [you practice]. If you practice with your fingers, no amount is enough. If you practice with your head, two hours is plenty.” Violin Professor Leopold Auer
One of the most important skills a consultant needs to learn and demonstrate is asking the right questions.
Of course, I frequently get the question, "How many cases should I do?" This, my dear friends, is not the right question.
It's almost always a means for an aggressively Type A person (the kind of person who gravitates towards consulting as an industry) to plan out their recruiting season, set benchmarks for themselves versus their peers, and make sure they're doing everything they need to get an offer. But this kind of question can't yield a useful output because there is not a straight line between "doing more cases" and actual improvement.
Most people view any experience with a task as a form of practice. Sure, you may learn things on the edges, but effective practice is deliberate practice. If you're unfamiliar with the concept, deliberate practice is a framework developed by Anders Ericsson to explain how expertise is developed among world-class performers. The five key pillars of deliberate practice are:
Pushing beyond your comfort zone.
Working towards specific, well-defined goals.
Focusing intently on practice activities with high-quality feedback.
Receiving and responding to high-quality feedback.
Developing a mental model of expertise.
Which of these do you accomplish through "doing cases" with non-experts?
If you are casing with people at your general skill level, you probably won't substantially exceed your comfort zone.
Sure, you can read casing books and define goals, but on your own, will you really know whether you hit them?
If you're just "doing cases," you may struggle to identify specific areas of improvement and struggle more to practice them in a targeted way.
If your feedback comes from non-experts, odds are it will not be of high quality.
How will you know what expertise looks like from the outside?
Learning how to case is a process of developing a number of hard and soft skills, learning new ways of thinking, and managing all of this new information so you can execute effectively every time you need to. The development of these skills, thought processes, and means of executing effectively can take time to build, but this process can be accelerated by leveraging deliberate practice techniques.
So, how many cases should you do? Enough. More importantly, how should you do them? Deliberately.
One Step at a Time
One essential skill for consulting candidates is mastering case math. While the math itself isn't usually difficult, the candidate must handle various tasks such as determining the appropriate methodology, gathering specific data points, and performing calculations, making it more of a challenge.
A common issue I've seen is casers attempting to tackle everything simultaneously, including asking questions, mentally calculating, structuring the problem, drawing conclusions, and inevitably becoming flustered and making errors.
So, how do the most successful casers handle this? They adopt a step-by-step approach: formula, data, calculation.
Start with the formula - understand your chosen methodology. It's best to develop multiple possible approaches (e.g., bottom-up vs. top-down) and work with the interviewer to assess if any data supports a particular method.
As you progress, request the necessary data. You may receive all, some, or none of what you ask for. If you get everything, it indicates you're on the right track. If you get none, consider an alternative approach. If you get some, use your judgment to evaluate your progress. If it seems like you can make reasonable estimations to fill data gaps, stick with your approach and suggest returning to estimating later.
(Throughout this process, if a number catches your attention, state why and ask questions related to it. For instance, "Oh, the market share is higher than expected. Does the company lack significant competitors? We can revisit this later, but I wanted to flag it now.")
Only after collecting the data should you proceed with calculations and drawing conclusions.
This approach offers several advantages. Firstly, it reduces errors by keeping numbers organized and minimizing mental math. Secondly, it showcases clarity of thinking, allowing the interviewer to follow your thought process in a well-structured manner. Lastly, it demonstrates client-friendliness since you can guide clients through your thinking step by step, even if they aren't as mathematically savvy as the interviewer.
During a case, multitasking is necessary. You must address specific questions, align them with the case's overall objective, and demonstrate clear thinking. Avoid overloading your mental capacity by attempting to tackle all aspects of case math simultaneously.
What else? Okay, what else?
A common question that interviewers ask in cases is "What else?" As in, "what could be the causes of profits dropping? Okay, what else? Okay, what else," and on and on ad infinitum.
Casers often look at this as a test of their a) creativity or b) business acumen. And sure, those are part of it. But what they miss is that it's really a test of their ability to structure a problem.
Let's look at an example.
Interviewer: The client's revenue is flat but their profits are declining. What could be the cause of this?
Caser: Well since Π = R - C, if revenue is flat, and profits are declining, costs must be increasing.
I: Great, which costs could it be?
C: (runs all cost line items possible through her head) I guess it could be labor, parts, land, interest, taxes, or something else?
I: Okay, what else?
C: Umm, maintenance cost?
I: Okay, what else?
C: …electricity?
I: Okay, what else?
C: Advertising?
I: Okay, what else?
C: … I don't know, that's all I can think of.
I: Okay, well we did some research and found out that the issue was that transaction costs were skyrocketing.
The caser has gotten herself into an impossible position. The interviewer is never going to stop asking what else, because the caser has gotten into a laundry list situation. There's no structure to her response, so there's no reasonable place for her to stop. It's not clear that she's reached the end of the list, or if the list even has an end to it. So how can this go differently?
Interviewer: The client's revenue is flat but their profits are declining. What could be the cause of this?
Caser: Costs must be increasing. (Note that you don't have to explain very simple concepts to the interviewer - they know that Π = R - C already.)
I: Great, which costs could it be?
C: So I'd break this down into fixed and variable costs. Are either of those specifically decreasing?
I: Not sure where the cost is, can you go a bit deeper?
C: Sure. Let's break down fixed costs physical capital costs, human capital costs, operating costs, and financing costs. For variable costs I would look at input costs, sales costs, transaction costs, transportation costs, and servicing costs. Are any of these areas increasing?
I: Yes, transaction costs are increasing.
Think about this in the context of a tree diagram. The first interviewer is building a list horizontally, at the bottom level of the tree diagram. That means that every new addition is a node on that tree, not attached to anything. The second caser is starting at the top of a tree diagram and working downward. This means that each new addition is refinement of an existing idea. It is generally much easier for people to go deeper than it is to go broader.
Like everything else in casing, these "what else" questions are all about understanding how you think. When in doubt, show the interviewer that your thinking is well structured.
The Magic Word
One of the most common things you'll hear from casing books and consulting firms is that they want casers to be "hypothesis-driven." Yet, many casers find themselves confused and unsure of how to apply this mindset to their approach. So, what exactly does it mean to be hypothesis-driven, and how can you tailor your approach to the case accordingly?
At its core, being hypothesis-driven means having a reason for every question you ask and every recommendation you make that ultimately ties back to the client's objective. This involves being both comprehensive in asking all the necessary questions and selective in only including relevant ones. For instance, when sizing a market, a methodology driven by the number and value of customers may not necessarily factor in the competitive landscape. Conversely, when looking to drive profit growth, asking about costs will almost certainly be relevant.
To demonstrate the connection between your actions and the case objective, use the magic word – "because." By structuring your requests for data, initial methodology, or conclusions in the form of "I need/want to look at/believe X because it indicates Y," you showcase your ability to form hypotheses, test them, and use that learning to solve a client problem.
As a caser, a great way to practice this approach is to use the word "because" in every sentence. Although it may sound a little crazy at first, this approach forces you to justify every aspect of your case and develop a discipline around having relevant reasons for your approach. If you can't find a "because," then the sentence doesn't deserve to be said.
Ultimately, mastering the art of being hypothesis-driven takes time, practice, and discipline. However, as someone who has interviewed over 1000 prospective consultants, I can confidently say that I would rather hire someone who overuses "because" than someone who cannot articulate their reasoning. After all, in consulting, every action must be justified, and the ability to do so concisely and coherently can make all the difference in the success of a project.
Closing the Case Like a Pro
When I would conduct interviews on campus, I always paid close attention to how candidates closed their cases, as it was indicative of their long-term potential at the firm, especially at the MBA/post-MBA level. There are a few key skills that distinguish the best casers and that you can incorporate into your wrap-up.
The first hurdle to clear is to wrap up logically. Have you accurately captured the information and drawn reasonable and clear conclusions from the data? If so, great, you have met the entry-level requirement. If not, passing the first round is highly unlikely.
The second hurdle to clear is to wrap up comprehensively. Have you mentioned the risks in your recommendations? Have you articulated next steps for the client to take? Does your recommendation have short-term and long-term implications that you can highlight? This is a good manager-level close, as it covers all the areas that the client cares about.
The final hurdle to clear is to wrap up productively. Have you thought about the next questions the firm could address? What new projects could this lead to? What new intellectual property could be developed? How can this project further benefit the firm? No more than a sentence or two is needed, but just with that, this is a partner-level close, as it demonstrates the kind of thinking that could reap dividends for the firm in the future.
So, given the choice, whom would you hire? Someone who can think logically? Someone who can think logically and comprehensively? Or someone who can also show the acumen to think productively? Which do you want to be?
Work Backwards from the Answer
When many casers start building out a methodology for a market sizing, one of the first things they say is "let's start with the population". Sure, in certain cases, you might have to size something up starting at the population, but that should almost never be where your thinking starts.
In a sizing, you generally have a target in mind, like a dollar value or number of customers/units. Population is about as far away from that ultimate objective as possible, and to get from population to the end, you're going to need to make a bunch of (hopefully lucky) guesses.
So what's the better way to approach it? Start at the goal, and work backwards. For example, if you're solving for total market size in dollars, step one should be "we're going to need the average price and total units sold. Do we have any of that data?" If they have both, great, you're done! If they only have price, that's fine too, because you've at least uncovered one of the major data points needed. Then you just have to figure out what to break down total units into. For example, "Let's break down total units into number of transactions per year and units per transaction."
The "start with population" method is like trying to hit a bullseye on the dart board from across a room. Sure, you might do it, but it's hard and you're probably not going to be all that accurate. Working backwards is like putting the dart right in the bullseye and then walking backwards to the line. Sure, it's a lot less of a challenge, but you hit the bullseye. Take the W.
Not only is starting at the goal and working backwards a more accurate approach, it's also easier to explain to the interviewer or client. By showing them your methodology in a step-by-step fashion, you're demonstrating clarity of thinking and a client-friendly approach. Plus, it reduces errors. When you know what you're solving for, it's much easier to keep the numbers straight and avoid mistakes.
So next time you're faced with a market sizing problem, remember: don't start with the population. Instead, start at the goal and work backwards. You'll hit the bullseye every time.
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